A variety of vessels for manipulating fluids and/or for carrying out chemical, biochemical and/or biological reactions are available. For instance, biological materials (e.g., animal and plant cells) including, for example, mammalian, plant or insect cells and microbial cultures can be processed using bioreactors. Traditional bioreactors, which are typically designed as stationary pressurized vessels, or disposable bioreactors, many of which utilize plastic sterile bags, may be used. Although reaction systems and other fluid manipulating systems (e.g., mixing systems) are known, improvements to such systems would be beneficial.